1. Field of the Invention
The present invention relates to a rubber plug fitting apparatus for fitting a rubber plug on an end portion of a wire.
2. Description of the Related Art
The present disclosure relates to subject matters contained in Japanese Patent Application Laid-Open No. HEI 7-7833, filed on May 2, 1994, the disclosure of which is expressly incorporated herein by reference in its entirety. FIGS. 1 to 3 are schematic configuration views illustrating respective steps of the rubber plug fitting apparatus. In FIGS. 1 to 3, a rubber plug feeding unit 2, a rubber plug positioning unit 3 and a rubber plug holder 4 are respectively arranged at 90xc2x0 intervals around a rotation center of a rotary unit 1 and at positions corresponding to an outer periphery thereof.
The rotary unit 1 has rubber plug holding rods 1a which are respectively arranged at 90xc2x0 intervals and which are rotationally movable. The rubber plug feeding unit 2 has a rubber plug accommodation passage 2a where a number of rubber plugs 5 are arranged, and it comprises an inside pin 2b which is movable from a position where the inside pin 2b is inserted into a wire passing-through hole (not shown) of the forefront one of the rubber plugs 5 which have been accommodated in the rubber plug accommodation passage 2a up to a position where the forefront rubber plug 5 abuts on the rubber plug holding rod 1a of the rotary unit 1, and a pushing rod 2c for pushing the forefront rubber plug 5 onto the rubber plug holding rod 1a of the rotary unit 1.
The rubber plug positioning unit 3 has a positioning plate 3a formed with a small hole 3b, and the positioning plate 3a is movable between a spaced position (shown in FIG. 1) where it is spaced from the rotary unit 1 and an approached position (shown in FIGS. 2 and 3) where it approaches to the rotary unit 1. Also, the rubber plug holder 4 comprises a pair of rubber holding portions 4a, 4a which can be opened/closed and which are movable between a spaced position (shown in FIG. 3) where they are spaced from the rotary unit 1 and an approached position (shown in FIGS. 1, 2) where they approach to the rotary unit 1, and a pair of wire guide portions 4b, 4b which can be opened/closed and which are movable between a spaced position (shown in FIGS. 1, 2) where they are spaced from the pair of rubber plug holding portions 4a, 4a and an approached position (shown in FIG. 1) where they approach to the pair of rubber plug holding portions 4a, 4a. A wire W whose outer cover has been stripped at its end portion Wa is disposed at a position corresponding to the rubber plug holder 4.
Next, operation of the above structure will be explained. Each rubber plug holding rod 1a of the rotary unit 1 is stopped at positions corresponding to the rubber plug feeding unit 2, the rubber plug positioning unit 3 and the rubber plug holder 4 sequentially according to rotation of the rotary unit 1. Then, at the position corresponding to the rubber plug feeding unit 2, the inside pin 2b is caused to pass through the wire passing-through hole of the forefront one of the rubber plugs 5 which have been accommodated in the rubber plug accommodation passage 2a and a leading end of the forefront rubber 5 is caused to abut on the rubber plug holding rod 1a. Next, the pushing rod 2c pushes the forefront rubber plug 5 to the rubber plug holding rod 1a side, and, by the pushing force of the pushing rod 2c, the rubber plug 5 is guided by the inside pin 2b to be fitted on the rubber plug holding rod 1a. At the position corresponding to the rubber plug positioning unit 3, the positioning plate 3a is moved from the spaced position to the approached position. In the course of movement of the positioning plate 3a, the rubber plug 5 is pushed by the positioning plate 3a while the rubber plug holding rod 1a is being inserted into the small hole 3b. By this pushing, the rubber plug 5 is fitted up to a predetermined position on the rubber plug holding rod 1a. At the position corresponding to the rubber plug holder 4, the rubber plug 5 is released from the rubber plug holding rod 1a by the pair of rubber holding portions 4a, 4a and the pair of wire guide portions 4b, 4b, and the rubber plug 5 which has been released is fitted on the wire W.
In the conventional rubber plug fitting apparatus, however, since the inside pin 2b is inserted into the rubber plug 5 so as to guide the same, it is necessary to set the diameter of the inside pin 2b to be equal to or less than the inner diameter (diameter of the wire passing-through hole) of the rubber plug 5. Accordingly, for a rubber plug 5 with a very small inner diameter, the diameter of the inside pin 2b is reduced according to the very small inner diameter, and the inside pin 2b is easy to break, which results in lack of durability of the inside pin 2b. 
Also, since positioning the rubber plug 5 which has been fitted on the rubber plug holding rod 1a is performed by the rubber plug positioning unit 3 independent of the rubber plug feeding unit 2, there is a problem where, in view of the whole body of the conventional rubber plug fitting apparatus, its structure becomes complicated and its manufacturing cost is increased.
In view of the above, the present invention has been achieved, and an object thereof is to provide an inexpensive rubber plug fitting apparatus which can perform a fitting of a rubber plug on a wire without any possibility of injury of parts or the like irrespective of the inner diameter of a rubber plug, which has an excellent durability, and which can perform a positioning of the rubber plug with a simple structure where a dedicated positioning unit is not used.
According to a first aspect of the present invention, there is provided a rubber plug fitting apparatus, comprising: a rubber plug feeding unit for feeding each of rubber plugs to a rubber plug feeding port; a rubber plug holder for holding one of the rubber plugs to fit the rubber plug on an end portion of a wire; and a rotary unit having a plurality of rubber plug holding rods which are fitted into each of the rubber plugs to hold the rubber plugs, the rotary unit rotationally moving each of the rubber plug holding rods between the rubber plug feeding unit and the rubber plug holder so that each of the rubber plugs can be delivered from the rubber plug feeding unit to the rubber plug holder through each of the rubber plug holding rods, wherein a pair of rubber plug guides are provided so as to be capable of being opened/closed at a side of the rubber plug feeding port of the rubber plug feeding unit; and wherein guide grooves are respectively provided at positions of the pair of rubber plug guides facing the rubber plug feeding port, so that the guide grooves guide an outer periphery of each of the rubber plugs which moves from the rubber plug feeding port to a side of each rubber plug holding rod when the pair of rubber plug guides are closed.
In the rubber plug fitting apparatus according to the first aspect, since a rubber plug is fitted on each of rubber plug holding rods by guiding the outer periphery of the rubber plug by respective grooves of a pair of rubber plug guides, there occurs no weak portion on the pair of rubber plug guides even when the inner diameter of the rubber plug is small, fitting of the rubber plug can be performed without injuring parts of the rubber plug fitting apparatus or the like irrespective of the diameter of the rubber plug, and the durability of a rubber plug fitting apparatus can be improved. Also, since there occurs no trouble such as a part injury and a rubber feeding can be surely carried out, the rubber plug fitting apparatus is prevented from being stopped due to any feeding failure, which results in improvement in productivity.
According to a second aspect of the present invention, as it depends from the first aspect, there is provided a rubber plug fitting apparatus, wherein stopper portions are respectively provided at the respective guide grooves of the pair of rubber plug guides so that the stopper portions restrict movement stroke of the rubber plug where the rubber plug moves from the rubber plug feeding port to the side of the rubber plug holding rod.
In the rubber plug fitting apparatus according to the second aspect, since stopper portions for restricting movement of a rubber plug moving from a rubber plug feeding port to a side of each rubber plug holding rod are respectively provided at respective guide grooves of a pair of rubber plug guides, a rubber plug is fitted up to a position on each rubber plug holding rod the where it abuts on the respective stopper portions, so that the rubber plug can be positioned on a predetermined position on each rubber plug holding rod. Thereby, positioning a rubber plug can be performed with a simple structure and without using a dedicated unit, so that cost of the whole body of the apparatus can be reduced. Also, since a step of positioning a rubber plug can be omitted, productivity can be further improved owing to the omission.